Hemolysis was significantly less common when blood was drawn with a butterfly needle as opposed to an intravenous catheter, researchers found.

Hemolysis was significantly less common when blood was drawn with a butterfly needle as opposed to an intravenous catheter, researchers found.

In a cross-sectional, prospective study of emergency department blood draws, use of an intravenous catheter was associated with a nearly eight-fold increased odds of hemolysis (OR 7.7, 95% CI 4.9-12.0) versus use of a butterfly needle, according to Polly Bijur, PhD, of Albert Einstein College of Medicine in Bronx, N.Y., and colleagues.

Hemolysis following intravenous catheter blood draws was significantly higher with small-gauge catheters, with collection tubes that were half full or less, when tourniquet time was a minute or greater, and in the event of difficult venipuncture, all factors not associated with hemolysis in butterfly needle blood draws, they wrote online in the journal Academic Emergency Medicine.

Hemolysis is a common issue with emergency department blood specimens, which occurs at rates varying from 8.1% to 32% in the U.S., a range that falls outside of the 2% "best-practice benchmark" established by the American Society of Clinical Pathology, the authors noted.

In the study, the investigators evaluated associations between hemolysis rate and device used in phlebotomy through a prospective, observational, cross-sectional analysis of 4,513 blood specimens with complete data on the emergency department blood draw.

Draws were carried out by emergency department staff, who were able to choose the device and size of the needle and recorded study-relevant data on the blood draw.

Devices included a butterfly needle collection set, a push-button blood collection set with 21- or 23-gauge butterfly needles, or a closed intravenous catheter system with dual-port intravenous catheters. Data collected included rate of hemolysis, device used, bore size of the needle or catheter, tourniquet time, difficulty sticking the patient, and amount of blood collected. Time, difficulty, and blood quantity were estimates observed by the staff member conducting the collection.

Hemolysis occurred in 12.5% of blood draws overall, with 14.6% occurring in patients who received a draw with an intravenous catheter and 2.7% of those who had blood drawn with a butterfly needle -- an 11.9 percentage-point difference. Associations between device used and rate of hemolysis were significant after adjustment for difficulty of venipuncture and other draw characteristics.

Associations between device use and hemolysis were "more than three times larger than the odds ratio for any other characteristic" the authors compared. In addition, "none of the characteristics of the blood draw were associated with the rate of hemolysis in blood drawn via butterfly needle."

They concluded that a change from intravenous catheter blood draw to butterfly needle phlebotomy would reduce the rate of hemolysis without requiring any other procedure alterations.

They did note that the study was limited by identifying information about the staff member drawing blood, and was not controlled for level of staff conducting the drawing. The study was also limited by lack of data on patient characteristics, such as severity of illness, age, or sex, as well as by the single-center collection of data, since results may differ at other centers and affect the outcome's generalizability.

The authors declared that they had no conflicts of interest to disclose.

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